1. Field of the Invention
The present invention relate to an apparatus for recording/reproducing real-time data and a control method therefor, and more particularly, but not by way of limitation, to an apparatus which records real-time data so that trick-play is available and a method for controlling the apparatus.
2. Description of the Related Art
Real-time data are the data that we usually deal with in our daily lives. Take a video camera for example. When we capture images of objects using a video camera, the video camera simply records video signals corresponding to motion of the objects seen by the video camera on a recording medium. In this case, the video signals are recorded on the recording medium as they are obtained, that is, no control information is added or no data processing is conducted before they are recorded. Such video signal is an example of real-time data.
Another example of real-time data is the data captured by CCTV""s commonly used in banks, companies, or museums. The data captured by CCTV""s are continuously recorded on a recording medium as long as the recording medium has free space to store the data, wherein the data obtained from a plurality of cameras are sequentially recorded on a single recording medium.
In other words, real-time data means raw data which have not been modified or processed before being recorded on a recording medium and therefore contain no additional control information for playback of the data. As a result, users do not know which data are recorded in which part of the recording medium.
As opposed to real-time data, we also deal with processed data. In the case of a video data, video data captured by a video camera can be recorded on a recording medium after being modified. Control information can be added to the video data for later access to the data. Such data are called processed data.
Music data or movie data recorded on a CD or DVD are a popular example of processed data which we commonly deal with. Since such music or movie data contain control information indicative of which data are recorded on which part of the disk, users can selectively play back specific data of interest by referring to the control data.
To sum up, real-time data are defined as data recorded on a recording medium in such a way that users do not know which data are recorded on which part of the recording medium, whereas process data are defined as data recorded on a recording medium together with control data pertaining to the location of the data on the recording medium so that users can selectively access specific data.
Therefore, processed data may be played back in various ways as long as the reproducing apparatus supports. For example, a music CD can be played back in higher speeds as well as normal speed. This is because a specific part of the recorded data can be selectively played once the CD player recognizes and interprets the control data contained in the music data recorded on the CD.
A general DVD can contain video images corresponding to a scene captured from up to 9 different angles and control data pertaining to each angle data are recorded together with the video data on the DVD. Thus, if a DVD player recognizes the control data, it can locate the video data related to a specific view angle chosen by a user and play back only the angle data.
As mentioned above, a recording medium containing processed data can be played back in several different ways such as high-speed playback and playback of a specific angle data. In contrast to normal playback of data, such a playback scheme is called trick-play.
Control data are inevitable for trick-play and so such trick-play is not available with real-time data, which are simply recorded on a recording medium with no additional control data. In a CCTV system, video data obtained by a plurality of cameras are sequentially recorded on a recording medium, with no additional information on which data are captured by which camera. Hence, it is impossible to selectively play back the video data captured by a specific camera.
Likewise, it is also impossible to play back recorded data in a high speed until the video data captured by a specific camera appear, because control data related to each camera are needed for locating the video data captured by the chosen camera and the reproducing apparatus should recognize the control data for locating the video data captured by the specific camera. Conventional apparatuses simply record incoming real-time data and thus are not capable of trick-play due to lack of control data.
It is an object of the present invention to provide an apparatus for recording real-time data which enables trick-play of the recorded real-time data and a control method for the apparatus.
The apparatus for recording/reproducing real-time data according to the present invention comprises recording means for sequentially recording incoming real-time video data on a recording medium, storing means for storing information on the recording position of the sequentially recorded video data by classifying the information in accordance with signal sources, and control means for controlling the recording means in order to record the stored information on the recording position in a particular part of the recording medium.
The apparatus for recording/reproducing real-time data according to the present invention further comprises change detection means for detecting a change in video data by comparing incoming video data with the video data received right before the incoming video data, wherein the recording means only records incoming video data which differs from the compared video data obtained previously.
The method for recording/reproducing real-time data according to the present invention comprises the steps of sequentially recording incoming real-time video data on a recording medium, storing information on the recording position of the sequentially recorded video data in a storing means after dividing the information according to signal sources, and recording the information on recording position in a particular part of the recording medium.